The purpose of licensure is that it effectively allows the licensed individual to hold themselves hostage in a negotiation. Without licenses, Management says "add feature X", and even though you know feature X is evil personified, you look at the pros and cons of implementing it or not, and you end up with "my professional conscience" vs "getting fired". With licenses, you end up with "every future job" vs "this job" which is quite a bit more balanced in the direction of "don't add evil feature X".